Acoustic properties of hybrid glass/flax and glass/jute composites consisting of different stacking sequences

Natural fibres offer good acoustic properties due to their structures; hence natural fibre reinforced composites have been widely used as sound absorber materials for structural applications in recent years. This study aims to explore the relationship between sound absorption properties and stacking sequence of natural fibre and hybrid composites. Hybrid laminates consisted of glass/flax and glass/jute fabrics with various stacking sequences were produced using vacuum infusion method. Sound absorption coefficient and sound transmission loss (STL) of composites were measured through a medium type impedance tube with four microphones at frequencies from 100 to 3500 Hz. Results showed that composite laminates made from hybrid fabrics showed higher sound absorption coefficient than glass and natural (jute and flax) fibre composites. Stacking sequence played a critical role whilst
using natural fibres at the face region offered higher sound absorption coefficient than using them at cores. It was observed that natural fibre and hybrid composites had higher transmission losses compared to glass composites, and less amount of sound were transmitted through when natural fibres were used at the outer region.